Hi,

I have two 5 kw Deye inverters connected in parallel. Both inverters connect to a single 10kwh Lithium battery.

When I look at Solar Assistant graphs I can see, by looking at battery current on each inverter, that one inverter is using energy from the battery and the other inverter is charging the battery. How can I configure both inverters to use battery power first before grid power?

 

Can you post a pic of how the inverters and battery are connected? 

Unfortunately I don’t have a schematic but I have a photo (not sure if it help). The inverter on the left is setup as the master and the one on the right is the slave.

Edited April 13, 20232 yr by QB87

Something is up with the wiring I think.. here is my current graph for a parallel install

How can I diagnose with my multi-meter if there is a wiring issue? 

I have the inverter and battery manuals so if someone can point me to go measure at X and Y on battery and/or inverter I can do that.

10 minutes ago, QB87 said:

How can I diagnose with my multi-meter if there is a wiring issue? 

I have the inverter and battery manuals so if someone can point me to go measure at X and Y on battery and/or inverter I can do that.

I'm not sure tbh - i think you may need to et your installer out to check.

When you are charging / discharging the batteries do the loads on the inverters keep up with each other, e.g. If you are charging at 2.5kw, is each inverter providing 1.25kw to the battery or is one doing more than the other (by a large margin)? 

So based on the latest images the inverters are working well in tandem for load etc - its just the battery current side of things that look wonky - very bizarre.

Thank you.

I do have another question if you don’t mind.

As mentioned, I have two 5 kw Deye inverters connected in parallel, ons is master and other is slave. Both inverters connect to a single 10kwh Lithium battery (LFP200-51.2) (https://www.solarwaysuppliers.co.za/wp-content/uploads/2014/01/Y-and-R-Solar-pty-Ltd-LES-Powerwall-Battery-Pack-User-Manual.pdf)

 

When my swimming pool pump turns on during load shedding my inverters stop providing power to the load, circuit breakers don’t trip. With a two 5kw inverters and a 10kwh battery I would assume the system should be able to handle the swimming pool pump!? See load image below, the spike when pump kicks in. Load is smaller than 5000w. In the battery current image below, the total battery current (yellow) is at 65 amps which is lower than the 100 amps. So nut sure why the inverter stops powering the load.

I would like to understand how I should configure each inverter in terms of the parameters below as I think that might be the problem:

1) Max charge/discharge current

2) Power setting under the Work Mode schedule
 

Max charge/discharge current

I see from the battery spec sheet that it’s max charge/discharge current is 100 amps. Since I have two inverters I set the max charge/discharge current on each inverter at 50 amps. My reasoning is that each inverter will pull 50 amps to get to the max 100 amps of the battery. Is this reasoning correct? 
 

Power Settings Under Work Mode schedule

The work mode settings I refer to is where you can configure the inverter to charge at certain times of the day using grid or battery. For each of the timeslots in this schedule you can edit the power. Currently I have set the power to 5000 for each timeslot. But wanted to know if this is correct? With the current battery specs, can I increase the power?

 

Good day. Have you sorted this issue of the two inverters running in parallel? I'm having same issue and know of at least 4 other people who have the same problem.

Hi, when connecting in parallel I see battery comms from battery bank only to master ? Does the slave also need battery comms as I see the slave drawing battery power while the master is not ?

I am also running 2 x 5 kW Sunsynk's in parallel and it all depends on the connected PV input power. Say the max PV for Master = 3 kW and Slave = 5 kW

When an AC load of say 8 kW is drawn, each inverter will supply +- 4 kW. In this case it will show the the master is discharging the battery, whilst the slave will be charging the battery.

The only way for the inverters to balance the load is to balance it out on the 48 V DC side, thus showing charge/discharge. Switching off the PV input on the master the discharge for both inverters will be the same.

The master inverter is controlling the whole operation. Comms cable and CT only connected to the Master inverter.

Hi Oom, I have bank of 3 batteries connected to bother inverters. 10 panels on one inverter and 8 on the other. Will adding 2 more to make them both 10 fix this or is not really a problem one charging and the other discharging?